Search Results for: light field

Light field cameras are now commercially available and capture much more information about the rays of light reflected from the scene. This enables us to perform functions like changing the focus of an image after it has been captured.

We previously learnt how to derive a Jacobian which relates the velocity of a point, defined relative to one coordinate frame, to the velocity relative to a different coordinate frame. Now we extend that to the 3D case.

The light we see is a mixture of different wavelengths in the visible region of the electromagnetic spectrum. The most common source of light is incandescence from a very hot body such as our sun or the filament of an old-fashioned light bulb. The spectrum, the amount of energy as a function wavelength, follows Planck’s […]

Incandescent light sources emit a lot of infrared radiation which we cannot see but can sense as heat. Non-incandescent sources such as fluorescent lights, cathode ray tubes and LEDs have quite different spectrums. When light travels through an absorbing medium, such as the atmosphere or water, different wavelengths are absorbed differently and this alters its […]

Many technologies have been developed to determine the 3D-structure of the world. RGBD sensors such as the Kinect use structured light, projecting a pattern of light onto the scene and observing how it is distorted. Time of flight sensors measure the time it takes for a pulse of light to travel from the camera to […]

Most objects reflect the light that falls on them and there are two aspects to this reflection. The first is geometric and concerned with the directions of the light rays: it can be specular reflection from a mirror like surface, or scattered Lambertian reflection from a matte surface. The second is the reflectance function which […]

Let’s look at how light rays reflected from an object can form an image. We use the simple geometry of a pinhole camera to describe how points in a three-dimensional scene are projected on to a two-dimensional image plane.

We learn how to use information from three magnetometers to determine the direction of the Earth’s north magnetic pole.

We learn the principles behind magnetometers, sensors that measure the Earth’s magnetic field.

Light entering our eyes stimulates the photoreceptor cells in the retina of our eye: color sensitive cone cells that we use in normal lighting conditions and monochromatic rod cells we use in low light. The density of these cells varies across the retina, it is high in the fovea, low in the peripheral vision region […]